JP5963410B2 - Flow path device and fluid mixing method - Google Patents

Description

  The present invention relates to a flow path device having a flow path for mixing a plurality of fluids and a method for mixing fluids.

  Obtaining desired information such as concentration and composition in order to confirm the progress and results of chemical and biochemical reactions is a fundamental matter of analytical chemistry, and various devices and sensors for obtaining such information are available. Invented. There is a concept called a micro total analysis system (μ-TAS) or a lab-on-a-chip, which aims to realize all processes from micronization of these devices and sensors to obtaining desired information on a microdevice. This is because the collected raw materials and unpurified specimens are passed through the flow path in the microdevice, and then the final chemical synthesis and the concentration of the components contained in the specimens are passed through processes such as specimen purification and chemical reaction. It is a concept that aims to obtain In addition, microdevices that control these analyzes and reactions inevitably handle minute amounts of solutions and gases, and are often called microchannel devices or microfluidic devices.

  Compared to conventional desktop-sized analytical instruments, the volume of fluid contained in the device is reduced by using a micro-channel device, so the reaction time is shortened by reducing the amount of necessary reagents and reducing the amount of analyte. There is expected. As the advantages of such microchannel devices are recognized, the technology related to μ-TAS is attracting attention.

  On the other hand, a new feature is created by converting a desktop-sized device into a microdevice. As an example, there is an increase in specific interface area or fluid mixing promotion only by molecular diffusion, and a phenomenon that can be ignored in a desktop-size analytical instrument becomes important in a microdevice. In particular, it is important to efficiently mix a plurality of solutions in a flow path in order to carry out a chemical reaction. However, in a micro flow path, a plurality of solutions flowing in the same direction are combined to form a laminar flow. This causes a phenomenon that mixing is difficult to proceed.

  As a method for promoting mixing in a micro flow path, Patent Document 1 discloses a deep groove type microreactor in which a laminar flow having a contact surface parallel to the depth direction is made larger in depth than the width of the flow path. It has been shown to form.

Japanese Patent Laying-Open No. 2007-050320 (FIG. 4B)

  The microreactor described in Patent Document 1 has a structure in which both of the two flow paths before joining are deep grooves, and after joining, the same deep groove width is joined.

  For this reason, it is difficult to accurately control the amount of both liquids at the time of merging, and the mixing ratio may not be uniform in the direction along the interface.

  Therefore, this is not a problem from the viewpoint of a reactor that performs a large amount of reaction synthesis, but in the field such as μ-TAS in which a test reaction process such as PCR is performed later, quantitative control may be difficult and is more preferable. A new form was required.

  The present invention has been made in view of such background art, and it is not necessary to actively manipulate the fluid flowing through the flow path, and can be easily manufactured and promotes fluid mixing while controlling the mixing amount. The present invention provides a flow channel device that can be used and a fluid mixing method using the same.

The microfluidic device that solves the above-described problems includes first to third inlets for supplying first to third fluids, respectively, and first to third flow paths connected to the first to third inlets. the a merge channel which are sequentially connected in the first and second junction with respect to the first to third flow path, and mixing channel arranged downstream of the confluent channel, and wherein said first The first merge point is configured to be capable of forming a two-layer flow in which the first fluid and the second fluid are stacked in a predetermined direction, and the second merge point is the two-layer flow On the other hand, it is configured to be able to form a three-layer flow in which the third fluid is laminated in the predetermined direction, and the mixing channel has a length in the predetermined direction at an end of the merged channel. Has a cross section longer than the cross section of the merging channel .

  According to the present invention, it is possible to form a laminar flow so that the contact interface direction becomes larger in the downstream enlarged flow channel after a plurality of fluids are merged in the merge flow channel. Thereby, it is easy to quantitatively control the fluids at the time of merging, and it is possible to provide a flow path device that mixes quickly.

It is a conceptual diagram which shows the principle of the flow-path device of this invention. It is a figure which shows one Embodiment of the flow-path device of this invention. It is a conceptual diagram which shows one embodiment of 2 liquid mixing using the flow-path device of this invention. It is a channel sectional view of one embodiment of two liquid mixing using a channel device of the present invention. It is a conceptual diagram which shows one embodiment of 2 liquid mixing using the flow-path device of this invention. It is a channel sectional view of one embodiment of two liquid mixing using a channel device of the present invention. It is a conceptual diagram which shows one embodiment of 3 liquid mixing using the flow-path device of this invention. It is a channel sectional view of one embodiment of 3 liquid mixing using a channel device of the present invention. It is a conceptual diagram which shows one embodiment which mixes 4 or more liquids using the flow-path device of this invention.

  Hereinafter, the present invention will be described in detail. In particular, when there is no description regarding the XYZ direction axis, among the channels formed on the substrate, the plane in the direction parallel to the substrate surface is the channel width direction, and the plane in the direction perpendicular to the substrate surface is the channel height. This will be described as the direction.

  A device according to the present invention includes at least two flow paths for flowing a fluid, a merge flow path that merges the fluids of the two flow paths to form an interface with the respective fluids, and a downstream of the merge flow path And a mixing channel whose cross section with respect to the flow direction is longer in the direction in which the interface is larger than that of the merged channel.

  A fluid mixing method according to the present invention is a fluid mixing method using a flow path device having at least two flow paths and a merging flow path for merging the fluids of the two flow paths. Fluids are allowed to flow from two flow paths, interfaces are formed in the combined flow paths, and the interfaces between the fluids are increased downstream of the combined flow paths.

  The flow channel device has a first substrate on which a groove serving as a mixing flow channel is formed, and an enlarged flow channel portion that increases in the depth direction of the groove as the mixing flow channel moves away from the merging flow channel. It is preferable that the configuration having the top surface of the enlarged flow path portion is the bottom surface of the second substrate.

  Still further, a first flow path is formed on the first substrate, a second flow path is formed on the second substrate, and an end of the first flow path is connected to the second flow path to join the second substrate. A flow path device is formed by joining the second substrate and the first substrate so as to form a flow path, and the end of the merged flow path is substantially the end of the flow path formed on the first substrate. It is preferable to connect to the part.

  Alternatively, a first flow path having a branch on the first substrate and a second flow path having a branch on the second substrate are formed, and one end of the first flow path is connected to the second flow path. A second confluence channel formed on the second substrate is formed, and one end of the second channel is connected to the first channel and the first substrate is formed on the first substrate. A microfluidic device in which a confluence channel is formed and a second substrate and a first substrate are joined such that an end of the first confluence channel is connected to the second confluence channel; It is preferable that an end portion of the two merging flow paths is connected to a substantially end portion of the flow path formed on the first substrate.

  And it is good to set it as the structure which has a bending flow path for changing the direction of an interface in a confluence | merging flow path. A plurality of channels for mixing, supply ports connected to the channels, and the like can be integrated on one region side with respect to the mixing channel formed with deep grooves. As a result, the other region can be used as a region for forming the channel after mixing, and therefore, it can be further integrated.

  In the joining at the time of manufacturing the flow channel device of the present invention, the height of the cross-sectional area of the flow channel is larger than the width, considering the manufacturing error at the time of joining, than the micro flow channel having a shape whose width is larger than the height. In addition, bonding can be performed while maintaining the cross-sectional area of the microchannel.

  The flow channel device of the present invention is suitably implemented as a so-called micro flow channel in a micro flow channel device having a size of at least one of width, height, and length on the order of μm, that is, 0.1 μm to 500 μm.

For example, in a micro flow channel having a width of 50 μm and a height of 20 μm, if the height direction is crushed by 1 μm by the pressure during bonding, the cross-sectional area is 95 μm ² . On the other hand, the width 20 [mu] m, in microchannel height 50 [mu] m, when there are the same manufacturing errors, the cross-sectional area becomes closer 98 .mu.m ² becomes, the originally intended 100 [mu] m ^2. Therefore, when it is going to produce a micro channel with a plastic material etc., in order to maintain a channel cross-sectional area, it is advantageous that the channel height is larger than the width. Here, in the method of promoting mixing by forming the laminar flow in multiple layers, the multi-layer laminar flow is formed so that the interface is formed in the width direction of the cross-sectional area of the microchannel, and the interface area of the laminar flow is Promote mixing by increasing the size. However, it is not optimal for mixing when the height of the microchannel is larger than that in the width direction because a laminar flow is formed in the direction where the interface area is small.

In the present invention, a laminar flow is formed in a microchannel, but whether a fluid flow in a specific channel forms a laminar flow or a turbulent flow can be estimated by the Reynolds number (Re). Is possible and the following formula:
Re = UL / ν
Led by. Here, the U representative speed, L is the representative length, and ν is the kinematic viscosity coefficient. Although there is no numerical value that is a strict boundary, it is generally considered that if the Reynolds number is lower than 2000, the fluid of the system forms a laminar flow. In fact, it is known that the Reynolds number is low in the case of a microchannel, and the value is usually lower than 100 and often less than 1. Therefore, in the microchannel, the fluid flow is considered to form a laminar flow. It's okay. Therefore, when a plurality of fluids are injected into the same microchannel, the flow of each fluid proceeds without being mixed except in the vicinity of the contacting interface. Unless otherwise specified, the flow path in the present invention has a low Reynolds number, so that the fluid flowing through the flow path is sized to form a laminar flow.

Since the mixing of fluids in the microchannel is a very small field, it is not easy to physically stir, and the influence of gravity is so small that it can be almost ignored. Therefore, the mixing depends on the diffusion of molecules. From the Einstein-Smoluchowski theory, the relationship between the diffusion time (t) of the molecule in one dimension, the diffusion distance (σ) and the diffusion coefficient (D) of the fluid,
t = σ ² / 2D
It has been known. Now, the diffusion time is proportional to w ² / D, where w is the channel width of a microchannel.

Now, it is assumed that two types of fluids are flowing in a micro flow channel having a flow channel cross-sectional area of 100 μm and a flow channel height of 20 μm, each having a cross-sectional area of 50 μm wide and 20 μm high. At this time, the moving distance necessary for the diffusion of the molecules constituting each fluid is a maximum of 50 μm. Therefore, when the diffusion coefficient of the molecules is 1 × 10 ⁻⁶ cm ² / s, the time required for the movement of the molecules is 12.5. Seconds. On the other hand, although the microchannels have the same cross-sectional area, the molecular flow of the two types of fluid flowing while having a channel width of 20 μm and a channel height of 100 μm and a cross-sectional area of 10 μm width and 100 μm height respectively. The time required for the movement is 0.5 seconds. That is, the travel time is reduced to 1/25 by reducing the distance required for diffusion to 1/5.

Furthermore, when the amount of molecules passing through the interface formed by laminar flow is defined as flux (J), cross-sectional area (A), and time (t),
J ・ A ・ t
Determined by. Since mixing is promoted when the amount of molecules passing through the interface is larger, the mixing efficiency is proportional to the cross-sectional area of the interface. For example, in a micro flow channel having a flow channel width of 20 μm, a flow channel height of 100 μm, and a cross-sectional area of 100 μm ² , four laminar flows have two kinds of fluids alternately having a cross-sectional area of 5 μm wide and 100 μm high. When the molecular diffusion coefficient is 1 × 10 ⁻⁶ cm ² / s, the time required for the movement of the molecule is 0.125 seconds. Compared with the state in which two laminar flows are flowing through microchannels having the same cross-sectional area, the interface area is tripled, and the corresponding contribution is included in the mixing time.

  That is, by forming a multi-layer laminar flow, reducing the diffusion distance necessary for mixing and maintaining a large interface area are important factors for increasing the mixing efficiency.

  The present invention utilizes the above principle to form a multi-layered laminar flow in the direction in which the interface area increases in the microchannel and to mix a plurality of fluids in the microchannel. In the following description, a laminar flow formed by two fluids is described as a two-layer flow, and a laminar flow formed by three fluids is described as a three-layer flow.

  FIG. 1 is a conceptual diagram showing an embodiment in which a laminar flow is formed while keeping the interface area of the device of the present invention large. Hereinafter, it demonstrates in detail using FIG.

  In the device of the present embodiment, the merging channel 12 is bent at a substantially right angle at the end portion 13 and connected to the mixing channel 14 while being displaced in the Z-axis direction. The merging channel 12 forms a laminar flow when a plurality of fluids merge, and has a size that makes it difficult for fluid mixing to proceed except for the contact interface.

  The mixing channel 14 disposed downstream of the merge channel has an aspect ratio of channel width to channel height that is greater than that of the merge channel, where the X axis direction is the channel width and the Z axis direction is the channel height. Largely formed.

  That is, the area of the laminar contact interface is increased by providing a mixing channel downstream in the direction (Z-axis direction) in which the cross section with respect to the flow direction (Y-axis direction) increases in the interface (Z-axis direction). Will be able to promote mixing.

  As shown in FIG. 1, the connection portion between the merging flow channel 12 and the mixing flow channel 14 is an enlargement in which the flow channel height is gradually changed so as to gradually increase the aspect ratio as the distance from the position of the end portion 13 increases. The flow path portion may be provided as a part of the mixing flow path. In such a structure, the merging channel 12 is produced on one substrate, the mixing channel 14 is produced on another substrate, and the end portion 13 is made to coincide with the position of the substantially end portion of the mixing channel 14; It can be manufactured by joining two substrates so that the merging channel 12 and the mixing channel 14 are substantially perpendicular.

  FIG. 2 shows a specific example in which the flow path device of this embodiment is configured by joining two substrates. The first substrate 18 having the mixing flow path 14 and the second substrate having a part of the merge flow path 13 are joined to form a flow path device. In the mixing channel 14, an enlarged channel portion 16 that increases in the depth direction of the groove as the distance from the merging channel 13 is formed at a connection portion with the merging channel 13.

  2A corresponds to a cross-sectional view of the flow channel device of FIG. 1 viewed from the X-axis direction, and FIG. 2B is a cross-sectional view taken along the lines AA ′ and BB ′ of FIG. The flow channel cross-sectional shape is schematically shown.

  In this embodiment, the fluid 10 and the fluid 11 are fluids that can be mixed with each other to form a two-layer flow that overlaps in the Z-axis direction, and first flow in the merging channel 12 in the X-axis direction. When the fluid 10 and the fluid 11 bend substantially at right angles to the negative direction of the Z-axis at the end 13 of the merging channel 12, they become fluid 10 'and fluid 11', respectively. At this time, the fluid 10 'is positioned in the positive direction of the X axis as compared with the fluid 11', and the two-layer flow is maintained. The fluid 10 ′ and the fluid 11 ′ flow while maintaining a roughly two-layer flow in the mixing channel 14 extending in the Y-axis direction, but at a point where the channel height of the mixing channel 14 has a value larger than the channel width. Form fluid 10 '' and fluid 11 '', respectively. Therefore, compared with the case where the fluid 10 ″ and the fluid 11 ″ exist in the merge channel 12 as the fluid 10 and the fluid 11, respectively, the contact interface increases, and the efficiency of mixing the two fluids increases. The progress of mixing is shown as 15. That is, as shown in FIG. 2B, the cross-sectional shape of the flow channel in the flow direction of the mixing flow channel 14 is longer than the merged flow channel 12 in the direction in which the interface increases (Z-axis direction). . The normal direction (X-axis direction) of the interface is preferably the same width from the viewpoint of manufacturing, but may be different.

  In FIG. 1, the fluid 10 and the fluid 11 flow through the merging flow path 12 while forming a two-layer flow overlapping in the Z-axis direction. The formation of the two-layer flow is performed by the following method. Can be achieved. A merging channel 12 for flowing the fluid 10 is made on one substrate, a micro channel for supplying the fluid 11 is made on another substrate, and the two substrates are joined so as to intersect the merging channel 12 This can be achieved. At this time, it is preferable that the micro flow path for supplying the fluid 11 and the mixing flow path 14 are formed on the same substrate. Further, the ratio of the fluid width to the channel height of the merging channel 12 is arbitrary, but it is desirable that the channel width is approximately 100 μm or less in order to reduce the area occupied by the entire microfluidic device. Furthermore, a small amount of the fluid 10 and the fluid 11 are mixed at the contact interface formed in the merging channel 12, but when the purpose is to uniformly mix in the mixing channel 14, the merging channel A small amount of mixing can occur at 12.

  The material of the device that forms the merging channel 12 and the mixing channel 14 does not need to be particularly limited, such as glass, ceramic, semiconductor, or a hybrid thereof. In order to increase the size, it is easy to produce a plastic material. This is because if the plastic material is used, the flow path can be formed by a relatively inexpensive method such as machining or injection molding even if the flow path height is larger than the flow path width.

  The fluid 10 and the fluid 11 are not particularly limited as long as they are miscible with each other. Further, the main components of the fluid 10 and the fluid 11 may be the same. For example, although the main component of the fluid 10 and the fluid 11 is water, both of them contain a water-soluble substance, and the reaction of the substance is started by mixing the fluid 10 and the fluid 11. Alternatively, the fluid 10 may include a water-soluble specimen, and the fluid 11 may be a reagent mainly composed of water.

  The method for forming a laminar flow in the direction in which the contact interface area increases when laminar flow is formed in the microchannel has been described above, and a method for forming a laminar flow in multiple layers will be described through examples.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, the following examples are examples for explaining the present invention in more detail, and the embodiments are not limited to the following examples.

Example 1
In Example 1, a multi-layer laminar flow is formed in a microchannel, and the multi-layer laminar flow is formed in a direction in which the contact interface area is increased by changing the direction of the laminar flow. This will be described with reference to FIG.

  FIG. 3 is a perspective view showing inlets and flow paths in the microfluidic device. The flow path indicated by a solid line is a flow path prepared on the second substrate, and the flow path indicated by a broken line is a flow path manufactured on the first substrate. The groove formed on the second substrate and the planar portion of the first substrate, or the groove formed on the first substrate and the planar portion of the second substrate are aligned and joined to each other. A flow path is formed on the substrate. However, in 24, 24 ′, 26, and 28 in FIG. 3, the flow path formed on the second substrate and the flow path formed on the first substrate intersect with each other. Connected with displacement in direction.

  The fluid 20 contained in the second inlet flows through the flow path 22 having a branch. The fluid 21 contained in the first inlet flows through the flow path 23 having a branch. The flow path 20 and the fluid 21 are substances that can be mixed with each other. The flow path 23 merges with the flow path 22 at the merge point 24. At this time, the fluid 21 flowing through the flow path 23 joins the fluid 20 at the joining point 24 while being displaced in the positive direction of the Z axis. And in the confluence | merging flow path 25, the fluid 20 and the fluid 21 form a two-layer flow in the direction in which the fluid 20 is in the positive direction of the Z axis. FIG. 4A shows a ZX cross-sectional view at the junction 24.

  On the other hand, the fluid 20 and the fluid 21 flowing in the direction of the joining point 24 ′ in the flow path 22 and the flow path 23 are respectively in contact with the fluid 21 while the fluid 20 is displaced in the negative direction of the Z axis at the joining point 24 ′. Merge and flow through the merge channel 25 ′. FIG. 4B shows a state of the fluid 20 and the fluid 21 flowing in the joining point 24 ′ and the joining flow path 25 ′, and a ZX sectional view in the vicinity of the joining point 24 ′. Since the fluid 20 merges with the fluid 21 with a displacement in the negative direction of the Z axis from the flow channel 22, the two-layer flow in which the fluid 20 is in the positive direction of the Z axis in the merged flow channel 25 ′. Form.

  The merge channel 25 and the merge channel 25 ′ merge at a further merge point 26. The flow of the fluid at this time is shown in FIG. The two-layer flow that flows through the merge channel 25 ′ merges with the two-layer flow that flows through the merge channel 25 while being displaced in the positive direction of the Z axis, so that a four-layer flow is formed in the merge channel 27. . At this time, the formation direction of the laminar flow in the merging channel 25 and the merging channel 25 ′ is unchanged even if it passes through the merging point 26. In addition, although it is the angle produced on XY plane when the merge flow path 25 and the merge flow path 25 'merge, when it is 180 degrees, the laminar flow which flows through each flow path may not be maintained. The angle should not be 180 degrees. Preferably, it is greater than 0 degree and approximately 45 degrees or less.

  The four-layer flow flowing through the merge channel 27 is connected to the mixing channel 29 at a substantially right angle at the end portion 28. The state of the fluid at this time is shown in FIG. The four-layer flow flowing through the merge channel 27 is displaced in the negative direction of the Z-axis at the end portion 28, whereby the laminar flow overlapping in the Z-axis direction is converted into a laminar flow overlapping in the X-axis direction. . The laminar flow subjected to the direction change flows through the mixing channel 29 in the Y-axis direction while maintaining the overlap in the X-axis direction. Since the mixing channel 29 is a channel whose channel height (Z-axis direction) is larger than the channel width (X-axis direction), the contact interface area formed by the laminar flow is large. Therefore, since a multi-layer laminar flow can be formed while keeping the interface area large, mixing is greatly promoted.

  In order to adjust the mixing ratio of the fluid 20 and the fluid 21, the flow rates of the fluid 20 and the fluid 21 can be arbitrarily set by adjusting the pressure applied to the second and first inlets. In addition, the mixing ratio can be confirmed by observing the width of each laminar flow in the mixing channel 29 to confirm the amount of fluid injected into the mixing channel 29.

  As described above, in the present invention, it is possible to form a multi-layer laminar flow in the direction in which the interface area increases by joining two substrates while having a structure with displacement in the Z-axis direction. In order to increase the interface area, for example, a method of increasing the width of the merge channel 27 on the XY plane is conceivable. However, the area in the XY plane direction increases, which is disadvantageous for device integration. That is, if the channel width of the mixing channel 29 is smaller than the channel height as in the present invention, the area in the XY plane direction required for mixing is reduced, and a device more suitable for integration is manufactured. It also has an effect that can be done.

(Example 2)
In Example 2, a method of the present invention for forming a multi-layer laminar flow using a mixing channel and forming a multi-layer laminar flow in a direction in which the contact interface area increases will be described with reference to FIGS.

  FIG. 5 is a perspective view showing inlets and flow paths in the microfluidic device. The flow path indicated by a solid line is a flow path prepared on the second substrate, and the flow path indicated by a broken line is a flow path manufactured on the first substrate. The groove formed on the second substrate and the planar portion of the first substrate, or the groove formed on the first substrate and the planar portion of the second substrate are aligned and joined to each other. A flow path is formed on the substrate. However, in 44, 44'46, and 46 'in FIG. 5, the flow path made on the second substrate and the flow path made on the first substrate intersect with each other, so that the flow path is high. Connected with displacement in direction.

  The fluid 40 contained in the second inlet branches and flows into the flow path 42 and the flow path 42 '. The fluid 41 contained in the first inlet branches and flows into the flow path 43 and the flow path 43 '. The end portions of the flow channel 43 and the flow channel 43 ′ are connected to the flow channel 42 and the flow channel 42 ′, respectively, and the position thereof is set as a merging point 44. The fluid 41 joins the fluid 40 while being displaced in the positive direction of the Z axis at the joining point 44. The situation at this time is shown in FIG. A two-layer flow in which the fluid 40 is in the positive direction of the Z axis with respect to the fluid 41 is formed in the merge channel 45. Similarly, in the merging channel 45 ′, the fluid 41 merges with the fluid 40 at the merging point 44 ′, and a two-layer flow in a state where the fluid 40 is in the positive direction of the Z axis with respect to the fluid 41 is formed. Is done.

  As shown in FIG. 6B, the fluid flowing through the merge channel 45 is displaced in the negative direction of the Z axis, as shown in FIG. 6B, and the direction of the laminar flow is X from the direction overlapping the Z axis direction. It is converted to the direction that overlaps the axial direction. And it flows to the junction point 47 of the mixing channel 48 while maintaining the direction of this laminar flow. On the other hand, the fluid flowing through the confluence channel 45 ′ is displaced in the negative direction of the Z-axis at the end 46 ′, and the direction in which the two-layer flow is overlapped in the Y-axis direction from the direction overlapping the Z-axis direction. Is converted to And it flows to the merge point 47 of the mixing channel 48 while maintaining the direction of the two-layer flow.

  The junction point 47 is a junction point that is arranged in the mixing channel 48 and does not involve displacement in the Z-axis direction. That is, the flow coming from the end portion 46 and the end portion 46 ′ forms a two-layer flow that is superposed in the X-axis direction. Since the flow immediately before the junction point 47 is a two-layer flow, as shown in FIG. 6C which is a cross-sectional view of the XY plane, a four-layer flow is formed when passing through the junction point 47. Furthermore, since the four-layer flow that travels through the mixing channel 48 is formed in a direction in which the contact interface area is large, mixing proceeds rapidly.

  As described above, the present invention can promote mixing by forming a multilayer laminar flow suitable for mixing in the mixing channel.

(Example 3)
As Example 3, a method for quickly mixing three or more kinds of fluids will be described with reference to FIGS.

  There is a microfluidic device that includes a fluid 60 in a second inlet, a fluid 61 in a first inlet, and a fluid 62 in a third inlet. The fluid flowing from each inlet forms a multi-layered laminar flow while flowing toward the mixing channel 68 and is mixed in the mixing channel 68. In FIG. 7, the part indicated by a solid line is a flow path formed on the second substrate, and the part indicated by a broken line is a flow path formed on the first substrate. ', 64, 64' and ends 66, 66 'are connected to each other. That is, this microfluidic device is composed of two substrates while there are three types of fluids to be mixed.

  The fluid 61 merges with the fluid 60 at the merge point 63 with displacement in the Z-axis direction, and a two-layer flow is formed such that the fluid 60 is in the positive direction of the Z-axis with respect to the fluid 61. The state of the fluid at this time is shown in FIG. Next, the fluid 62 is merged at the merge point 64 so as to form a third layer in the negative direction of the Z-axis of the two-layer flow composed of the fluid 60 and the fluid 61 to form a three-layer flow. It flows through the merge channel 65. The state of the fluid 60, the fluid 61, and the fluid 62 at this time is as shown in FIG.

  At the end portion 66 of the merging channel 65, the three-layer flow is converted into a flow in which the direction of the three-layer flow is overlapped in the X-axis direction by changing the flow in the negative direction of the Z-axis. It flows toward the confluence point 67. FIG. 8C shows the direction of the three-layer flow at this time. Similarly, the fluid that has passed through the joining points 63 ′, 64 ′ and the joining flow path 65 ′ also forms a three-layer flow, and is converted into a flow in which the direction of the three-layer flow overlaps the Y-axis direction at the end 66 ′. It flows through the mixing channel 68 toward the junction point 67.

  FIG. 8D illustrates a state of fluid flow in the vicinity of the confluence point 67 in a cross-sectional view on the XY plane. The two three-layer flows formed by the fluid 60, the fluid 61, and the fluid 62 go to the joining point 67 that is not displaced in the Z-axis direction. Since the mixing channel 68 is sized so that the Reynolds number is low, when the two three-layer flows merge at the merge point 67, a six-layer flow is formed. By forming a six-layer flow in the mixing channel 68, the distance of molecular diffusion required for mixing is reduced, and the width (X-axis direction) of the mixing channel 68 is high (Z-axis direction). ) Is larger, the interface area is also kept large, so that the mixing is easily promoted.

  In FIG. 7, three types of fluids are mixed, but more types of fluids can be mixed by the following method. When necessary, a flow path is formed in the first substrate in the direction of the end portions 66 and 66 ′ from the merge points 64 and 64 ′, and the flow path is connected to the merge flow paths 65 and 65 ′ with a negative Z-axis. This can be realized by connecting so as to merge from the direction. The inlet and each flow path at this time are shown in FIG. That is, it is possible to cope with mixing of four or more kinds of fluids simply by creating a new flow path in parallel with the flow path having the same structure as the flow path of the fluid 62 in FIG. 7 in the first substrate. .

  As described above, the present invention is not specialized for mixing two kinds of fluids. Therefore, when mixing three or more kinds of fluids, it is necessary to repeatedly arrange all parts of the structure for mixing two kinds of fluids. There is also an effect that the area required for mixing devices can be reduced. Furthermore, it is possible to cope with the mixing of four types and five types of fluids with an easy design change.

Example 4
As Example 4, in order to explain that the present invention is useful even when the fluid injected into the flow path is immiscible, a liquid-liquid extraction in a microfluidic device will be used as an example with reference to FIG. explain.

  The fluid 10 containing the specimen and the fluid 11 for extracting the specimen form a laminar flow that overlaps in the Z-axis direction in the merging channel 12. The specimen has affinity with the fluid 11, and is extracted into the fluid 11 when contacting the fluid 11. This extraction efficiency depends on the contact interface area between the fluid 10 and the fluid 11, and the extraction efficiency is higher when the contact interface area is larger.

  Now, the fluids 10 and 11 flowing in the confluence channel 12 are changed in the direction of the two-layer flow at the end 13 and flow to the mixing channel 14. In the liquid-liquid extraction, the fluid 10 and the fluid 11 are often immiscible with each other, and the two-layer flow overlapping in the X-axis direction is maintained also in the mixing channel 14. However, the width (X-axis direction) of the mixing channel 14 is higher than the height (Z-axis direction), and the contact interface area can be set larger than the two-layer flow in the merging channel 12. Therefore, the extraction efficiency of the specimen into the fluid 11 increases as the interface area increases.

  The specimen is, for example, toluene existing in an aqueous solution. When the fluid 10 is a mixture of water and toluene, and the fluid 11 is oil, the toluene in the aqueous solution can be extracted into the oil of the fluid 11.

  As described above, the present invention has an effect on a reaction in which it is essential to pass through an interface by forming a laminar flow in a direction in which the interface area increases in applications other than mixing fluids.

  The present invention can be used in a microfluidic device for performing chemical reaction and chemical analysis.

10, 10 ′, 10 ″ fluid 11, 11 ′, 11 ″ fluid 12 micro flow channel 13 end 14 mixing flow channel 15 fluid mixing state 20 fluid 21 fluid 22 flow channel 23 flow channel 24, 24 ′ merge Point 25 Junction channel 26 Junction point 27 Junction channel 28 End 29 Mixing channel 40 Fluid 41 Fluid 42, 42 'Channel 43, 43' Channel 44, 44 'Junction point 45, 45' Junction channel 46, 46 'end 47 merge point 48 mixing flow path 60 fluid 61 fluid 62 fluid 63, 63' merge point 64, 64 'merge point 65, 65' merge flow path 66, 66 'end 67 merge point 68 mixing flow path

Claims (5)

First to third inlets for supplying first to third fluids, respectively;
First to third flow paths connected to the first to third inlets ;
A merging channel sequentially connected at the first and second merging points with respect to the first to third channels, and a mixing channel disposed downstream of the merging channel ,
The first merge point is configured to be capable of forming a two-layer flow in which the first fluid and the second fluid are laminated in a predetermined direction, and the second merge point is the 2 The laminar flow is configured to be able to form a three-layer flow in which the third fluid is laminated in the predetermined direction. A microchannel device having a cross section whose length is longer than that of the merged channel. A first flow path that is a micro flow path having a branch on the first substrate and a second flow path that is a micro flow path having a branch on the second substrate are formed, and one end of the first flow path is A second merge channel formed on the second substrate is formed by connecting to the second channel, and one end of the second channel is connected to the first channel and the first A first merge channel formed on the substrate is formed, and the second substrate and the first substrate are joined so that an end of the first merge channel is connected to the second merge channel. Microchannel device . A mixing channel disposed downstream of the merge channel,
The second merging channel is configured to be capable of forming a four-layer flow stacked in a predetermined direction, and the mixing channel has a length in the predetermined direction at an end of the merging channel. Has a longer cross section than the cross section of the confluence channel
The microchannel device according to claim 2. The channel device, the mixing channel and becomes groove is provided on the first substrate, the mixing channel is merged flow channel expanding flow path portion increases in the depth direction of the groove with distance from the The microchannel device according to claim 3 , comprising: 5. The micro flow according to claim 4 , wherein the flow path device has the second substrate above the first substrate, and a top surface of the enlarged flow path portion is a bottom surface of the second substrate. Road device.

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